Direct Photocatalyzed Hydrogen Atom Transfer (HAT) for Aliphatic C–H Bonds Elaboration

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1875 - 1924

Опубликована: Авг. 6, 2021

Direct photocatalyzed hydrogen atom transfer (d-HAT) can be considered a method of choice for the elaboration aliphatic C–H bonds. In this manifold, photocatalyst (PCHAT) exploits energy photon to trigger homolytic cleavage such bonds in organic compounds. Selective bond may achieved by judicious abstractor (key parameters are electronic character and molecular structure), as well reaction additives. Different classes PCsHAT available, including aromatic ketones, xanthene dyes (Eosin Y), polyoxometalates, uranyl salts, metal-oxo porphyrin tris(amino)cyclopropenium radical dication. The processes (mainly C–C formation) most cases carried out under mild conditions with help visible light. aim review is offer comprehensive survey synthetic applications d-HAT.

Язык: Английский

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Visible Light-Induced Transition Metal Catalysis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1543 - 1625

Опубликована: Окт. 8, 2021

In recent years, visible light-induced transition metal catalysis has emerged as a new paradigm in organic photocatalysis, which led to the discovery of unprecedented transformations well improvement known reactions. this subfield complex serves double duty by harvesting photon energy and then enabling bond forming/breaking events mostly via single catalytic cycle, thus contrasting established dual photocatalysis an exogenous photosensitizer is employed. addition, approach often synergistically combines catalyst–substrate interaction with photoinduced process, feature that uncommon conventional photoredox chemistry. This Review describes early development advances emerging field.

Язык: Английский

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Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4237 - 4352

Опубликована: Янв. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Язык: Английский

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Alkoxy Radicals See the Light: New Paradigms of Photochemical Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2429 - 2486

Опубликована: Окт. 6, 2021

Alkoxy radicals are highly reactive species that have long been recognized as versatile intermediates in organic synthesis. However, their development has impeded due to a lack of convenient methods for generation. Thanks advances photoredox catalysis, enabling facile access alkoxy from bench-stable precursors and free alcohols under mild conditions, research interest this field renewed. This review comprehensively summarizes the recent progress radical-mediated transformations visible light irradiation. Elementary steps radical generation either or central reaction development; thus, each section is categorized discussed accordingly. Throughout review, we focused on different mechanisms well impact synthetic utilizations. Notably, catalytic abundant still early stage, providing intriguing opportunities exploit diverse paradigms.

Язык: Английский

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Radical C(sp3)–H functionalization and cross-coupling reactions

Nature Reviews Chemistry, Год журнала: 2022, Номер 6(6), С. 405 - 427

Опубликована: Май 17, 2022

Язык: Английский

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Direct excitation strategy for radical generation in organic synthesis

Chemical Society Reviews, Год журнала: 2021, Номер 50(11), С. 6320 - 6332

Опубликована: Янв. 1, 2021

This tutorial review encompasses the radical generation based on classical methods and photoredox catalysis. It will also focus only demanding visible-light, which involves EDA complex direct photo-excitation strategy.

Язык: Английский

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Site-Selective Direct C–H Pyridylation of Unactivated Alkanes by Triplet Excited Anthraquinone

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(7), С. 3003 - 3012

Опубликована: Фев. 8, 2021

Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction the broad field of research. Here, we report modular photochemical platform for site-selective pyridylation unactivated hydrocarbons via unique synergistic effects triplet excited anthraquinone an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective tertiary secondary C(sp3)-H bonds abundant was achieved by employing various N-aminopyridinium salts highly fashion, thus providing new catalytic system direct construction high-value-added compounds under ambient conditions. Moreover, this operationally simple protocol applicable to variety linear-, branched-, cyclo-alkanes more complex molecules with high degrees site selectivity visible-light conditions, which provides rapid straightforward access versatile synthons upgrading mild, metal-free

Язык: Английский

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Switchable Divergent Synthesis Using Photocatalysis

ACS Catalysis, Год журнала: 2022, Номер 12(3), С. 1857 - 1878

Опубликована: Янв. 20, 2022

A highly selective and divergent synthesis enables access to various molecules has garnered broad interest from not only organic chemists but also medicinal biologists who work with chemical libraries. Since the 20th century, such transformations have been achieved using transition-metal-catalyzed reactions, in which choice of catalyst or ligand crucially affects selectivity. Over past several decades, photocatalysts attracted a considerable amount attention because they provide additional ways control reaction intermediates product selectivity via electron energy transfer. From this perspective, we highlight recent development switchable syntheses photocatalysts, are difficult achieve classical catalytic transformations.

Язык: Английский

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Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(40), С. 16470 - 16485

Опубликована: Сен. 30, 2021

The value of catalytic dehydrogenation aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting inexpensive organophotoredox base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, process involves H atom transfer (HAT) form alkyl radicals, which then react with cobaloxime produce olefins H2. This operationally simple method enables direct readily available chemical feedstocks diversely functionalized olefins. For example, demonstrate, first time, oxidant-free desaturation thioethers amides alkenyl sulfides enamides, respectively. Moreover, system's exceptional site selectivity functional group tolerance are illustrated late-stage 14 biologically relevant molecules pharmaceutical ingredients. Mechanistic studies have revealed dual HAT provided insights into origin reactivity selectivity.

Язык: Английский

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Electronic control over site-selectivity in hydrogen atom transfer (HAT) based C(sp³)–H functionalization promoted by electrophilic reagents

Chemical Society Reviews, Год журнала: 2022, Номер 51(6), С. 2171 - 2223

Опубликована: Янв. 1, 2022

Leveraging on electronic effects in both the substrate and HAT reagent, site-selectivity can be implemented C(sp 3 )–H bond functionalization.

Язык: Английский

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